A PROBE OF DYNAMICAL MODELS USING FUNCTIONAL SENSITIVITY DENSITIES WITH APPLICATION TO HE-]HE+ PLUS NE(2P(5)3S) AND LI+I-]LI+ PLUS I-( PLUSNE(2P(6)))

The functional sensitivity densities delta ln sigma(12)(E)/delta ln V- ii(R) for He+ + Ne(2p(6)) --> He+ + Ne(2p(5)3s) reveal that the collis ional excitation cross section sigma(12)(E) is insensitive to the addi tional diabatic curve V-33 included in some models. The negligible sen sitivity sigma(12)(E) to V-33 offers a quantitative validation of the more popular two state model for collisional excitation of Ne by He+. The sensitivity profiles for the collisional ionization Li + I --> Li + I- modeled by crossing diabatic curves V-11 (covalent) and V-22 (io nic) shows that the ionization cross section does not depend on inner crossings even when these stem from large distortions in the underlyin g potential energy curves. The lack of sensitivity to inner crossings establishes the predominant role of the outermost crossing in triggeri ng nonadiabatic transitions.